Researchers have shown that the optimally weighted z-test, where the weights are the standardized expected difference in means, is more powerful than other methods when combining p-values from ...independent studies. However, in practice the effect for each independent study is usually unknown, which makes the optimally weighted z-test not applicable. A new test similar to the optimally weighted z-test, but with the effects being estimated from data, is derived. This new test is another generalized Fisher test which can be very powerful under certain situations. The new test is compared with existing methods through simulated data. Some suggestions for choosing tests to combine p-values from independent studies are given. The use of the new test is also illustrated by a real data application.
The conventional Z-test for correlation, grounded in classical statistics, is typically employed in situations devoid of vague information. However, real-world data often comes with inherent ...uncertainty, necessitating an adaptation of the Z-test using neutrosophic statistics. This paper introduces a modified Z-test for correlation designed to explore correlations in the presence of imprecise data. We will present the simulation to check the effect of the measure of indeterminacy on the evolution of type-I error and the power of the test. The application of this modification is illustrated through an examination of heartbeat and temperature data. Upon analyzing the heartbeat and temperature data, it is determined that, in the face of indeterminacy, the correlation between heartbeat and temperature emerges as significant. This highlights the importance of accounting for imprecise data when investigating relationships between variables.
Multi‐regional clinical trial (MRCT) is an efficient design to accelerate drug approval globally. Once the global efficacy of test drug is demonstrated, each local regulatory agency is required to ...prove effectiveness of test drug in their own population. Meanwhile, the ICH E5/E17 guideline recommends using data from other regions to help evaluate regional drug efficacy. However, one of the most challenges is how to manage to bridge data among multiple regions in an MRCT since various intrinsic and extrinsic factors exist among the participating regions. Furthermore, it is critical for a local agency to determine the proportion of information borrowing from other regions given the ethnic differences between target region and non‐target regions. To address these issues, we propose a discounting factor weighted Z statistic to adaptively borrow information from non‐target regions. In this weighted Z statistic, the weight is derived from a discounting factor in which the discounting factor denotes the proportion of information borrowing from non‐target regions. We consider three ways to construct discounting factors based on the degree of congruency between target and non‐target regions either using control group data, or treatment group data, or all data. We use the calibrated power prior to construct discounting factor based on scaled Kolmogorov–Smirnov statistic. Comprehensive simulation studies show that our method has desirable operating characteristics. Two examples are used to illustrate the applications of our proposed approach.
On one-sample Bayesian tests for the mean Abdelrazeq, Ibrahim; Al-Labadi, Luai; Alzaatreh, Ayman
Statistics (Berlin, DDR),
03/2020, Letnik:
54, Številka:
2
Journal Article
Recenzirano
Odprti dostop
This paper deals with a new Bayesian approach to the standard one-sample z- and t- tests. More specifically, let
be an independent random sample from a normal distribution with mean μ and variance
. ...The goal is to test the null hypothesis
against all possible alternatives. The approach is based on using the well-known formula of the Kullbak-Leibler divergence between two normal distributions (sampling and hypothesized distributions selected in an appropriate way). The change of the distance from a priori to a posteriori is compared through the relative belief ratio (a measure of evidence). Eliciting the prior, checking for prior-data conflict and bias are also considered. Many theoretical properties of the procedure have been developed. Besides it's simplicity, and unlike the classical approach, the new approach possesses attractive and distinctive features such as giving evidence in favour of the null hypothesis. It also avoids several undesirable paradoxes, such as Lindley's paradox that may be encountered by some existing Bayesian methods. The use of the approach has been illustrated through several examples.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Literary compositions are very often analyzed using various constituent units like words, phrases, sentences, and paragraphs. Unlike the conventional research that focuses on the aforementioned ...constituent units, our task is a statistical effort carried out on the most fundamental unit of any literary composition called varna, or character, followed by automated classification using learning algorithms. This article is a case study on the Hindi adaptations of two significant literary pieces, namely, Jana-Gaṇa-Mana and Vande-Mātaram, and acknowledging that the two songs being studied belong to different classes based on their bhava, i.e., the inherent emotion of the poem. The present task is the first of its kind that uses the concept of komala and kaṭhora varna to establish diversity between the two. The two-proportion Z-test is successfully applied to statistical data pertaining to the candidate songs, thereby reestablishing the theoretical assertions by investigating real pieces of literature. Taking the statistical verification as ground, a learning-based classification system is designed to yield the best accuracy of 85%, which further compliments the theory reestablished statistically.
The financial numbers game is unfortunately alive and doing well. One of the forensic accounting techniques is based on Benford’s Law and is used for the detection of unusual transactions, anomalies ...or trends. The aim of this paper is to test whether the financial statements of Croatian companies deviate from Benford’s Law distribution. The financial statements of 24 companies that are in the pre-bankruptcy settlement process and 24 companies that are not in the pre-bankruptcy settlement process were analysed using the Benford’s Law test of the first digit distribution for the period from 2015 to 2018. The data used to calculate the first digits of distribution were taken from the Zagreb Stock Exchange. The chi-square test has shown that the observed companies that are not in the process of pre-bankruptcy settlement do not have the first digit distribution which follows the Benford’s Law distribution. The Kolmogorov-Smirnov Z test has shown that the distribution of the first digits from the financial statements of companies listed on the Zagreb Stock Exchange fits to Benford’s Law distribution.
•The z test is employed to identify seismo-ionospheric anomalies in the GPS TEC.•The ROC curves are used to examine seismo-ionospheric precursors in China.•Youden index finds the optimal cutoff value ...for determining anomaly bounds.
Evidence of the seismo-ionospheric precursor (SIP) is reported by statistically investigating the relationship between the total electron content (TEC) in global ionosphere map (GIM) and 56M⩾6.0 earthquakes during 1998–2013 in China. A median-based method together with the z test is employed to examine the TEC variations 30days before and after the earthquake. It is found that the TEC significantly decreases 0600–1000 LT 1–6days before the earthquake, and anomalously increases in 3 time periods of 1300–1700 LT 12–15days; 0000–0500 LT 15–17days; and 0500–0900 LT 22–28days before the earthquake. The receiver operating characteristic (ROC) curve is then used to evaluate the efficiency of TEC for predicting M⩾6.0 earthquakes in China during a specified time period. Statistical results suggest that the SIP is the significant TEC reduction in the morning period of 0600–1000 LT. The SIP is further confirmed since the area under the ROC curve is positively associated with the earthquake magnitude.
The harmful effects of close inbreeding have been recognized for centuries and, with the rise of Mendelian genetics, was realized to be an effect of homozygosis. This historical background led to ...great interest in ways to quantify inbreeding, its depression effects on the phenotype and flow‐on effects on mate choice and other aspects of behavioral ecology. The mechanisms and cues used to avoid inbreeding are varied and include major histocompatibility complex (MHC) molecules and the peptides they transport as predictors of the degree of genetic relatedness. Here, we revisit and complement data from a Swedish population of sand lizards (Lacerta agilis) showing signs of inbreeding depression to assess the effects of genetic relatedness on pair formation in the wild. Parental pairs were less similar at the MHC than expected under random mating but mated at random with respect to microsatellite relatedness. MHC clustered in groups of RFLP bands but no partner preference was observed with respect to partner MHC cluster genotype. Male MHC band patterns were unrelated to their fertilization success in clutches selected for analysis on the basis of showing mixed paternity. Thus, our data suggest that MHC plays a role in pre‐copulatory, but not post‐copulatory partner association, suggesting that MHC is not the driver of fertilization bias and gamete recognition in sand lizards.
No evidence of inbreeding avoidance in a population of sand lizards (Lacerta agilis). In the same population, parental pairs exhibit a disassortative mating pattern with respect to MHC genotypes.
Purpose
To establish a single-nucleotide polymorphism-based analysis (SBA) method to identify triploidy in the miscarriage tissue by using low-coverage whole-genome sequencing (LC-WGS).
Methods
The ...method was established by fitting a quadratic curve model by counting the distribution of three heterozygous mutation content intervals. The triploid test result was mainly determined by the opening direction and the axis of symmetry of the quadratic curve, and
Z
test between the same batch samples was also used for auxiliary judgment.
Results
Two hundred thirteen diploid samples and 8 triploid samples were used for establishment of the analytical method and 203 unknown samples were used for blind testing. In the blind testing, we found 2 cases positive for triploidy. After chromosome microarray analysis (CMA) and mass spectrometry verification, we found that both samples were true positives. We randomly selected 5 samples from the negative samples for mass spectrometry verification, and the results showed that these samples were all true negatives.
Conclusions
Our method achieved accurate detection of triploidy in the miscarriage tissue and has the potential to detect more chromosomal abnormality types such as uniparental disomy (UPD) using a single LC-WGS approach.
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